Taulupe Faletau dives to score one of his three tries in Bath’s 44-20 victory against Gloucester that keeps their Premiership play-off hopes alive.Photograph: Jordan Mansfield/Getty Images

Bath have endured a curious campaign but, with one round to go, they are still arithmetically in the hunt for play-off participation. If the odds remain against them pipping Leicester for the fourth and final spot, they showed enough vim and vigour in this six-try demolition of their West Country rivals Gloucester to guarantee European Champions’ Cup rugby next season and confound some of their more jaundiced supporters.

A hat-trick of tries for their fit-again Wales and Lions No8, Taulupe Faletau, was the centrepiece of an increasingly assured team performance, a far cry from the Parisian horror show that cost them another date with Gloucester in Friday week’s Challenge Cup final. Interestingly, too, it came after the director of rugby, Todd Blackadder, omitted his Lions centre Jonathan Joseph and picked Rhys Priestland to start at fly-half ahead of George Ford.

It may be too little, too late in terms of fourth place – Leicester will require only a losing bonus point at Worcester to trump a four-try Bath win at Sale – but Blackadder duly received the response he wanted from his squad after their loss of composure against Stade Français.

While he insisted afterwards that Joseph and the Leicester-bound Ford needed a rest after a bruising few weeks, he also made it clear the whole squad need to find more consistency if Bath want to become title winners again. “We want this club to be a top-four club every single year and, when we don’t achieve that, questions have to be asked,” he said. “We can’t be happy with fifth or sixth every year, it’s not good enough.”

Gloucester, in contrast, still looked to be feeling the effects of their epic European semi-final victory at La Rochelle and David Humphreys, their director of rugby, made no attempt to deny their spectacular implosion from 10-8 down at half-time. “That 10-15 minutes after half-time was probably as bad as we’ve played in the last three years,” said Humphreys, whose side can now qualify for next season’s Champions’s Cup only via the European play‑offs which will also feature a Top 14 side and two teams from the Pro12. “It was embarrassing.”

Television pictures also suggested his reserve hooker Motu Matu’u was allowed to return to the field having been knocked cold early in the second half. Humphreys said the player had successfully passed his head injury assessment and had been diagnosed as suffering a temporary stinger rather than anything more serious but the authorities may opt to review the footage.

Happily Bath’s second-half display was rather more uplifting, even if the home side’s win was a relative one. Both these clubs have again trailed in behind Exeter and it is now four seasons since Gloucester finished above the Chiefs. They could yet prove awkward opponents for Rob Baxter’s side at Kingsholm in Saturday’s final round of the regular season but, as with Bath, they continue to be prone to huge fluctuations in form.

It was a perverse kind of day from the outset: a May bank holiday fixture with damp, blustery weather borrowed from winter and more Gloucester-born forwards in Bath’s front five than among their opposite numbers. Shaun Knight and Elliott Stooke, both former Cherry and White squad members, found themselves in blue, black and white and there were more Welsh internationals on the field – seven in total – than English ones.

Priestland and James Hook duly exchanged penalties as if it were Scarlets versus Ospreys and, from Kahn Fotuali’i’s clever chip, the former Newport Gwent Dragon Faletau scored the game’s opening try. It was something of a turn-up when Henry Trinder’s cross-kick found the lurking Jonny May wide on the right and an Englishman finally made it on to the scoresheet seven minutes before the break. It was only a brief interlude, Aled Brew finishing strongly on the left four minutes after the restart to extend the home lead to 17-8 and five minutes later the Welsh-born but English-reared centre Max Clark surged gloriously clear from 40m out. If Bath were missing Joseph and Ford, playing in his final home game for Bath, it was not instantly apparent.

Even a string of replacements could not save Gloucester, with Bath’s fresh legs proving the more influential. If Fotuali’i’s no-look pass to the recently arrived Robbie Fruean was a nice touch there was a genuine hunger about the way the New Zealander stormed past Charlie Sharples’s attempted tackle to ensure the try bonus point that keeps Bath’s play-off hopes theoretically alive. Faletau’s second and third tries in the 72nd and 77th minutes inflicted even more damage and left Blackadder upbeat despite belated late scores for May and David Halaifonua. “Taulupe was just unbelievable,” said the former All Black captain. “That was a world-class player right there.”